That's pretty common in academia. You publish something new that is worse than the state-of-the-art. To maintain some semblence of meaning for your work, you you then say that the shortcomings will be addressed in future papers. Often these papers never surface because somewhere along the way it turns out that even though your approach was new, it is fundamentally worse. This kind of stuff happens all the time in research and it only makes it to the surface thanks to this twisted publish or perish world academics now live in.